Conventional natural gas (Methane)^a

Global assessment of conventional methane in reserves and technically recoverable resources

16,000

4.4 × 10¹⁴

3.2 × 10²

U. S. methane consumption in 2008

23

6.5 × 10¹¹

4.7 × 10⁻¹

Methane in methane hydrate^b

Very early global estimates, based on many erroneous assumptions, of the methane content of gas hydrate

~35,000,000

~10¹⁸

~7.1 × 10⁵

Recent range of global estimates of methane in methane hydrate

35,000 to 177,000

1 × 10¹⁵ to 5 × 10¹⁵

7.1 × 10² to 3.6 × 10³

Mean MMS estimate of methane in hydrate in the Gulf of Mexico

21,000

6 × 10¹⁴

4.3 × 10²

Mean U. S. Geological Survey estimate of technically recoverable methane from hydrate on the North Slope of Alaska

85.4

2.4 × 10¹²

1.7

Estimate of methane in hydrate, eastern Nankai Trough, Japan

40

1.14 × 10¹²

8.1 × 10⁻¹

Atmospheric methane^c

Atmospheric abundance of methane

~250

~7 × 10¹²

~5

Estimate of total global flux of methane from all sources entering the atmosphere per year

30

8.4 × 10¹¹

0.6

Estimate of total global sink for all methane entering the atmosphere per year

29

8.1 × 10¹¹

0.58